With the development of touch control technologies, mobile products such as cellphones and tablet computers can accomplish almost all operations simply with one touch screen.
At present, apart from planar operations allowed in a traditional touch screen, operations perpendicular to the display screen are further increased, in order to improve the user experience. In this case, the user is capable of not only obtaining a tactile sensation corresponding to his/her operation, but also accomplishing different operations based on a magnitude of the force. For example, Apple Inc. has issued a cellphone having a pressure touch function, wherein a pressure sensor and a haptic engine are introduced into the original design. In such a cellphone, when the user presses the protection glass of the cellphone, the protection glass and the display assembly will be urged to generate a subtle deformation downwards, such that a distance between the display assembly and the pressure sensor is changed. Then, such a distance is measured by means of the pressure sensor, and from the measured distance, a magnitude of the pressure caused by the user's pressing of the protection glass is estimated rapidly in real time through complicated mathematical algorithms. After that, vibration of the haptic engine is triggered so as to provide real-time haptic feedbacks to the user.
However, in the above solution, the magnitude of the pressure caused by the user's pressing of the protection glass is estimated in a spatial approach, and thus the accuracy is far from being satisfactory. It can only distinguish between peak and pop, and thereby cannot provide actual haptic feedbacks to the user. Besides, according to the above solution, the haptic engine is required to calculate a vibration speed based on the magnitude of the pressure, and the haptic engine also needs to consume certain energy to obtain the desired speed, which leads to a rise in the overall power consumption.